Myco Glossary

Myco Glossary : a glossary of mycological terms.

This is a living list, always growing, so check back for more terms, and feel free to send in definitions in the comment section and I will add them in.

ABSORB - to obtain food by taking up water and dissolved substances across a membrane; this is how fungi operate.

ACTIVE TRANSPORT - the pumping of a substance across a cellular membrane from a point of lower concentration to one of higher concentration; requires energy.

AERO-AQUATIC FUNGI - pond-inhabiting fungi producing elaborate floating propagules which are on hand to colonize autumn-shed leaves as they fall into the water, then `condition’ them in near-anaerobic conditions at the bottom of the pond

AEROBIC - requiring free oxygen for respiration.

AEROBIOLOGY - the study of fungal (and other) propagules in the atmosphere. This has particular relevance for plant pathologists and for people with respiratory allergies.

AGAR - phycocolloid produced by the red alga, Gelidium; used to solidify culture media used in mycology and bacteriology.

AGARIC - a gill- or tube-bearing mushroom of the order Agaricales (Holobasidiomycetes).

ASCOMYCOTINA – Subphylum of Dikaryomycota; form endogenous meiospores in asci and have a restricted dikaryon; generally called Ascomycetes.

ASCOSPORE – meiospore produced in an ascus; usually 8 per ascus

ASCUS (pl. = ASCI) – the meiosporangium of the Ascomycetes: originally evolved as a spore-gun in terrestrial environments.

ASEPTIC – free or freed from contaminating organism(s); (of microbiological technique) pertains to working under sterile conditions and using sterile techniques, e.g., working in a laminar flow bench, using flame sterilized inoculating loops and instruments.

AUTOCLAVING – sterilization by steam under pressure (15 lb./in2) for prescribed time periods; better than dry heat, as sterilization is achieved at lower temperatures (121C).

BINOMIAL (or BINOMINAL) – the unique double name given to each known species: composed of generic epithet and a species, or `trivial’, epithet.

BIOCIDE – a substance which kills living organisms.

BIOCONTROL – the control of undesirable organisms by other organisms.

BIOCONVERSION – the enzyme-mediated conversion of organic substrates, such as cellulose, to other more valuable substances, such as protein, by other organisms.

BIODEGRADABLE – capable of being broken down by microorganisms (bacteria and/or fungi).

BIOLOGICAL ACCUMULATION – the acccumulation of toxic substances, e.g., DDT, in higher levels of the food web by consumption of organisms of the same or lower levels which have acquired the substance but which have not been affected by it.

BIOMASS – the total mass (amount) of living organism(s) in a particular area or volume.

BIOTECHNOLOGY – the large-scale exploitation of microorganisms, including fungi, to produce pharmaceuticals, feedstuffs, or other valuable metabolites.

BIOTROPHIC – growing on another living organism, in intimate association with its cytoplasm.

BLIGHT – a general name for many diseases of plants esp. when leaf damage is sudden and serious, e.g., potato blight, late blight (Phytophora infestans); early blight (Alternaria solani).

BOLETE – a fleshy agaric with tubes instead of gills.

BRACKET FUNGI – corky or woody, often perennial, basidiomata of the polypores. Also known as SHELF FUNGI.

CAP – the spreading, often umbrella-like, gill- or tube-bearing part of an agaric, more technically known as the pileus.

CARBOHYDRATE – organic compound consisting of a chain of carbon atoms to which hydrogen and oxygen are attached in a 2:1 ratio, e.g., sugars, starch, glycogen, cellulose.

CARCINOGENS – substances which induce cancer.

CARDINAL TEMPERATURES – the minimum, maximum and optimum temperatures of growth of an organism.

CELL – a unit of protoplasm containing a functional genome and often enclosed by a wall.

CELLULASE – an enzyme that can degrade cellulose; a cellulolytic enzyme.

CELLULOSE – principal polysaccharide of plant cell walls; a polymer of glucose; walls of Oomycetes are partly composed of a similar substance called `fungal cellulose’.

CHEMOTROPISM – growth of an organism up a chemical concentration gradient.

CHITIN – the principal polysaccharide in cell walls of most fungi (but not Oomycota);

CHLOROPLAST – a chlorophyll-containing plastid; the site of photosynthesis. Not found in fungi.

CHROMISTA – one of the seven Kingdoms. It is mentioned here because the Oomycota and the Hyphochytriomycota are atypical member groups, placed in it along with many photosynthesizing organisms

CIRCADIAN RHYTHMS – regular rhythms of growth and activity, which occur in an approximately 24-hour cycle.

CLAMP CONNECTIONS – short, backward directed branches on many dikaryotic basidiomycetous hyphae, providing a bypass for one of the nuclei produced during synchronous division of the dikaryon, insuring their equal distribution between the new cells; croziers are possible homologues.

CLASSIFICATION – the systematic arrangement of organisms, based on everything we know about them.

CLONING – producing organisms all of which contain copies of the same gene: the desired gene is removed from the donor, inserted into a vector (usually a plasmid), the vector is used to transform a host culture, then those hosts which have taken up the vector are selectively cultured.

COLONY - a discrete mycelium of a fungus, often derived from a single spore.

CONDITIONING – the process by which fungi must enzymically soften up substrates like dead leaves before the detritivorous animals can eat them.

COPROPHILOUS FUNGI – fungi living on dung; include many zygomycetes, ascomycetes and basidiomycetes.

CUP FUNGUS – a `discomycete’ – any ascomycete with an open, shallow, cupulate apothecial ascoma; a hetergeneous grouping because the asci may be unitunicate operculate, unitunicate inoperculate, or in many lichens, bitunicate.

CUTICLE – waxy or fatty layer on outer wall of epidermal cells.

CYANOBACTERIA – prokaryotic chlorophyllous organisms often capable of fixing nitrogen; also known as ‘blue-green algae.’

DAMPING-OFF – a rotting of seedlings at soil level; commonly caused by species of Pythium, Phytophthora, Fusarium, and Rhizoctonia.

DECIDUOUS – falling off, as leaves that are shed in the autumn; used to describe the sporangia of downy mildew fungi (Peronosporales: Oomycota).

DELIQUESCE – to liquefy; to autolyse, as in the gills of the agaric, Coprinus, or `Prototunicate’ asci.

DIKARYOTIC – having two separate but compatible nuclei in each cell or compartment; a nuclear condition unique to the fungi.

DNA (DEOXYRIBOSE NUCLEIC ACID) – carrier of genetic information in living organisms; composed of chains of phosphate, sugar molecules (deoxyribose), purines (guanine and adenine) and pyrimidines (cytosine and thymine); capable of self-replication as well as of determining RNA synthesis.

DNA LIGASE – an enzyme which repairs breaks in the phosphate backbone of DNA.

DNA SEQUENCING – determining the actual sequence of bases in parts of DNA or RNA molecules. The first fungus to be fully sequenced was Saccharomyces cerevisiae (Dijon et al., 1994. Nature 369:371)

DRY ROT – wood-rot caused by certain basidiomycetes, e.g., Serpula lacrymans (Meruliaceae: Aphyllophorales). A misnomer, because if the wood were really dry, it would not rot.

DUAL ORGANISMS – organisms which invariably consist of two interdependent symbionts, e.g. lichens. In fact, most plants are also dual or multiple organisms because of their intimate association with endo- or ecto-mycorrhizal fungi. The eukaryotic cell is widely believed to have arisen as a multiple symbiosis.

ECTOMYCORRHIZA or ECTOTROPHIC MYCORRHIZA - mycorrhiza in which a dikaryomycotan mycelium ramifies through the soil, forms a mantle around individual rootlets, and grows between cells of the root cortex, forming a Hartig net (the interface between the symbionts). The fungus exchanges phosphorus for photosynthates from the root. Many forest trees, esp. Pinaceae, Fagaceae, have ectomycorrhizal associations with agarics or boletes (cf. ENDOMYCORRHIZA); see MYCORRHIZA.

ENDEMIC – natural to (always present in) one geographical region.

ENDOMYCORRHIZA or ENDOTROPHIC MYCORRHIZA - an ancient symbiosis of fungi with green plants; hyphae gathering nutrients from the soil, esp. phosphorus, are continuous with others that grow between and within root cells and produce ARBUSCULES (q.v.); found in 90% of angiosperms and conifers, except Pinaceae; also called vesicular-arbuscular mycorrhizae (cf. ECTOMYCORRHIZA); see MYCORRHIZA.

ENDOPHYTIC FUNGI – fungi (such as some anamorphs of Clavicipitales) which grow systemically within plants without causing symptoms; now known to produce neurotoxins that discourage herbivores, and therefore to be participating in a mutualistic symbiosis.

ENDOSYMBIONT – an organism which lives in a mutualistic symbiosis within the cells of another organism.

ENZYME – a protein that, even in low concentration, speeds up (catalyzes) specific chemical reactions; usually becomes inactivated or unstable at high temperatures; ADAPTIVE enzymes are not produced until the presence of the substrate has been recognized.

EPIDEMIC – (of disease) prevalent and spreading rapidly among many individuals in a population at the same time.

EPIDERMIS – the surface tissue of plant organs, composed of living parenchyma cells.

EPITHET – one of the words which makes up the binomial of an organism.

FACULTATIVE – (of a parasite) able to live as a saprobe (cf. OBLIGATE, OPPORTUNISTIC).

FAIRY RING – mushrooms arising at the periphery of a radially spreading underground mycelium; common in grasslands, and around conifers.

FAMILY – taxonomic group above genus, but below order; suffix is -aceae.

FERMENTATION – chemical changes in organic substrates caused by enzymes of living microorganisms.

FUNGI (sing. = FUNGUS) – non-photosynthesizing (i.e., heterotrophic) eukaryotes that produce exoenzymes and absorb their food: usually producing, and living inside, a network of apically extending, branched tubes called hyphae; may belong to Kingdom Chromista or Kingdom Eumycota.

‘FUNGI IMPERFECTI’ – an unfortunate and obsolete name for anamorphic fungi which are, or are suspected to be, the anamorphs of ascomycetes or basidiomycetes; better called `conidial fungi.’ They are no less perfect than the teleomorphs some of them possess.

INGEST – to obtain food by engulfing it (as opposed to absorbing, which is what fungi do)

INOCULATE – to put a microorganism into an organism or a substratum.

INOCULUM – a small amount of a fungus used to inoculate fresh culture medium or to infect a host organism.

IRRADIATION – exposure to some form of radiant energy.

KINGDOM – the highest taxonomic category, of which 7 are currently recognized (Archaebacteria, Eubacteria, Protozoa, Chromista, Plantae, Eumycota, Animalia); all members of Kingdom Eumycota are fungi, and two of the phyla in Kingdom Chromista are also treated as fungi.

KOJI – a `starter’ consisting of Aspergillus oryzae cultured on roasted wheat or barley (for hamanatto) or A. orzyae or A. soyae cultured on rice (for miso), which is then inoculated on the appropriate substrate.

KOMBUCHA - The following have been isolated from ‘Kombucha tea’ Bacterium xylinum, Bacterium xylinoides, Bacterium gluconicum, Saccharomyces ludwigii, Saccharomyces apiculatus varieties, Schizosaccaromyces pombe, Acetobacter ketogenum, Torula varieties, Pichia fermantans and other yeasts. In other words, this is a really mixed bag which has occasionally had very deleterious effects.

LICHEN – a dual organism in which a fungus (usually an ascomycete) maintains a green alga or a cyanobacterium captive within its thallus in a symbiosis that approaches balanced parasitism. Some lichens consist of three or more symbionts.

LIGNIN – a polymer of phenylpropanoid units that is an important constituent of wood. It is resistant to biodegradation by most organisms, but can be degraded by many basidiomycetes.

MACROSCOPIC – big enough to be seen by the naked eye.

MAGIC MUSHROOMS – typically, hallucinogen-containing species of Psilocybe, but also spp. of Gymnopilus, Panaeolus, Conocybe, and Amanita muscaria.

MANTLE – a compact layer of hyphae enclosing short feeder roots of ectomycorrhizal plants; connected to the Hartig net on the inside, and to the extramatrical hyphae on the outside; acts as a sink for nutrients.

MEDIUM, culture – a substance or solution for the culture of microorganisms. DEFINED MEDIUM — of a prescribed composition, used for determining the biochemical capabilities of the organism, e.g., auxotrophs; COMPLETE MEDIUM — containing all nutrients required for growth; MINIMAL MEDIUM — the simplest chemically defined medium on which the wild type (prototroph) of a species will grow and which must be supplemented by one or more specific substances for the growth of auxotrophic mutants derived from the wild type; SELECTIVE MEDIUM – medium containing certain chemical components which restrict the growth of some microorganisms but encourages the growth of others.

METABOLISM – the sum of all chemical processes occurring within a living cell or organism; PRIMARY METABOLISM — metabolism associated with the normal maintenance and growth of the organism; SECONDARY METABOLISM — processes which use primary metabolites available after growth has ceased, producing substances with no known role in primary metabolism.

MICRON – one-thousandth of a millimetre or one-millionth of a metre: written as `m’.

MISO – an Oriental food product, used for soups and as flavouring agent, composed of rice and cereals + soybeans fermented by Aspergillus oryzaeand Saccharomyces rouxii.

MITOCHONDRIA – intracellular organelles concerned with the Krebs cycle and electron transport: the chief source of ATP in non-photosynthesizing cells.

MOLDS – see MOULDS.

MONOCULTURE – condition in which one species is grown in an extensive pure stand; describes most agricultural situations.

MOULDS – fungi, usually either zygomycetes or hyphomycetes, associated with deterioration of food or manufactured goods of organic origin.

MULTILOCULAR – with several to many internal spore-producing cavities or chambers.

MUSCARINE – toxic quaternary ammonium compound found in species of Clitocybe and Inocybe; causes perspiration-salivation-lacrymation syndrome.

MUSCIMOL – a hallucinogenic derivative of ibotenic acid; formed in Amanita muscaria when basidiomata are dried.

MUSHROOM – a fleshy basidioma, usually stalked and with a cap (pileus) beneath which gills or fleshy tubes are covered with or lined with the hymenium; edible or poisonous; see AGARIC, BOLETE.

MUTAGEN – an agent that increases the mutation rate.

MUTATION – a permanent change in a gene.

MUTANT – a mutated gene, or an organism carrying a gene that has undergone a mutation; may be biochemical, fermentation, resistance, suppressor, physiological, in nature.

MUTUALISM (MUTUALISTIC SYMBIOSIS) – a kind of symbiosis in which both or all partners gain from the association, e.g. mycorrhizae.

MYCELIUM (pl. = MYCELIA) – collective term for hyphae; the vegetative thallus of a fungus excluding organs of sporulation or sclerotia.

MYCOBIONT – the fungal partner in a symbiotic relationship (mycorrhiza or lichen).

MYCOHERBICIDE – a prepartion of phytopathogenic fungi used to kill weeds.

MYCOINSECTICIDE – a preparation of entomopathogenic fungi used to kill insects.

MYCOLOGY – the study of fungi.

MYCOPARASITE – a fungus which attacks other fungi (sometimes called HYPERPARASITE).

MYCOPHAGOUS – eating fungi.

MYCORRHIZA – symbiotic relationship between a filamentous fungus and the roots of a plant; see ECTOMYCORRHIZA, ENDOMYCORRHIZA.

MYCOTOXINS – fungal secondary metabolites which contaminate food and are poisonous to animals and humans.

NEMATODES – threadworms or roundworms; members of Phylum Nematoda, pseudocoelomate metazoa, 10,000 spp.; common in soil, decaying organic matter and as parasites of plants and animals.

NOMENCLATURE – the naming of Fungi is governed by the International Code of Botanical Nomenclature as adopted by each International Botanical Congress; any proposals to change the Code are published, debated, and voted on at such Congresses. If more than one name has been applied to a fungus, the rules help decide which is the proper one. The rules also allow separate binomials for anamorph and holomorph.

NUCLEUS – a specialized body within the eukaryotic cell bounded by a double membrane and containing the chromosomes.

OBLIGATE – invariably found in a particular situation; usually used in reference to organisms that must live in intimate association with a living host (cf. FACULTATIVE, OPPORTUNISTIC)..

PARASITIC – deriving nourishment from another living organism (the host) (cf. NECROTROPHIC, SAPROBIC).

PARTIAL VEIL – membrane enclosing gill cavity during development in some agarics; after rupture, it remains as a ring or annulus on the stipe (cf. UNIVERSAL VEIL).

PATHOGEN – an organism that causes disease.

PENICILLIN – an antibacterial antibiotic produced by Penicillium spp. (Hyphomycetes).

pH (potential Hydrogen) – a symbol for hydrogen ion concentration in a solution; pH values run from 0 to 14 on a logarithmic scale, the lower the value, the greater the concentration of hydrogen ions, and the more acidic a solution is; pH 7 is `neutral’, pH less than 7 is acidic, pH greater than 7 is alkaline or basic.

PHYCOBIONT – the algal partner in a symbiotic relationship, as in a lichen.

PHYTOBIONT – the plant partner in a mutualistic symbiosis, e.g. a mycorrhiza.

PILEUS – the spore-bearing cap or head of a mushroom or other large fungal fructification.

POLYMER – a compound made by linking many identical smaller molecules (monomers).

POLYPEPTIDES – organic compounds made up of amino-acids linked by peptide bonds.

POLYPORES – the shelf- or bracket-fungi; hymenomycetes living on dead (or sometimes living) trees and often producing perennial basidiomata in which the hymenium lines annual layers of corky, vertically oriented tubes.

POLYSACCHARIDE – a polymer made up of many linked monosaccharides, e.g., cellulose, a polymer of glucose.

ppb – parts per billion; a measure of concentration.

ppm – parts per million; a measure of concentration.

PREDACEOUS – preying upon other organisms, as in the nematode-exploiting fungi.

PRIMORDIUM – the first stage of development of an organ or sporoma.

PROTECTANT – a fungicide that can give protection from a pathogen by killing its spores or germ tubes while they are still outside the host, but cannot cure an existing infection (cf. ERADICANT).

PSILOCIN and PSILOCYBIN – hallucinogenic indoles found in many species of Psilocybe, and some species of Panaeolus,Gymnopilus and Conocybe.

RELATIVE HUMIDITY (RH) – an index of water content, expressed as a percentage of the saturated value.

RING – see PARTIAL VEIL.

RUSTS – plant diseases caused by obligately parasitic fungi (most are Uredinales: Teliomycetes, but the so-called white rust of brassicaceous plants is caused by an oomycete).

SAPROBE – a heterotrophic organism that derives food from dead organisms, or from organic substances liberated by living ones (cf. PARASITE, NECROTROPH, SYMBIONT).

SCLEROTIUM (pl. = SCLEROTIA) – a firm, frequently rounded, mass of hyphae with or without the addition of host tissue or soil, normally having no spores in or on it (cf. BULBIL, STROMA); a sclerotium may give rise to a fruit body, or mycelium.

SEM – scanning electron microscope. Objects are coated with a thin layer of a metal in a vacuum, and examined in an electron beam.

SOMATIC – pertaining to the vegetative or assimilative body of an organism.

SOREDIA (sing. = SOREDIUM) – lichen propagules — small aggregations of fungal hyphae around algal cells; formed by the break up of a thallus.

SPECIES – the lowest-ranking taxon normally used (though subspecies, variety and race are subspecific taxa); comprises individuals very similar in all major respects; often used for organisms that are normally capable of interbreeding; among anamorphic fungi has a mainly morphological/developmental connotation. The name of a species is called a binomial or binominal, and has two parts, a generic name which is capitalized, followed by a species epithet. Both words are italicized.

SPORE – specialized microscopic propagule, usually an agent of dispersal, in fungi, cryptogamic plants, many protozoa, chromista and bacteria: capable of developing into an adult without fusion with another cell. In fungi may be unicellular or composed of two to many cells.

SPORE PRINT – a visible deposit of basidiospores obtained by allowing an agaric to drop spores onto white paper overnight; the colour of this deposit is an important aid to identification.

SPORULATION – the production of spores.

STERILIZATION – the process whereby all microorganisms and their propagules are killed by exposure to heat (see AUTOCLAVING), radiation, or chemicals, or removed by filtration.

STIPE – a stalk which lacks true vascular tissue, as in mushrooms.

STIPITATE – stalked.

SUBICULUM – a wool- or crust-like growth of mycelium under fruit bodies.

SUBSTRATE – (1) the food of a fungus; (2) substance acted on by an enzyme; (3) the material from which a fungus is fruiting – e.g. polypores mostly occur on wood.

SURFACTANT – an agent which reduces the surface tension of a liquid, e.g., detergents.

SYMBIOSIS – a state of intimate association or living together; the relationship benefits both partners in MUTUALISTIC symbioses, or one partner at the expense of the other in PARASITISM, or may be neutral, as in COMMENSALISM.

SYSTEMIC – describes a fungicide or pathogen which enters and becomes widely distributed within the body of a plant or animal.

TAXONOMY – the classification of organisms on the basis of their evolutionary relationship; see CLASSIFICATION.

TEMPEH – an Oriental food made by fermenting soybeans with Rhizopus oligosporus.

TEONANACATL – `the Flesh of the Gods,’ magic mushrooms used in Central American curing and divining ceremonies.

TISSUE – a group of similar cells organized into a structural and functional unit.

TOADSTOOL – see MUSHROOM, AGARIC; toadstool is a confused term — it is assumed to refer to poisonous agarics, but many so-called toadstools are harmless; use `agaric’ instead, and join the cognoscenti.

TOOTH FUNGI – members of the family Hydnaceae (Aphyllophorales: Basidiomycetes) in which the hymenium covers downwardly directed teeth.

TRACE ELEMENTS – elements essential for growth, but required only in minute amounts.

TRUFFLE – an edible hypogeous ascoma of the genus Tuber (Pezizales: Ascomycetes). Can also be applied to the basidiomata of many hypogeous basidiomycetes, though these are not generally edible.

UNIVERSAL VEIL – membrane totally enclosing some young agaric basidiomata (as in Amanita); after rupture it remains as the volva around base of the stipe, and often also as scales on the cap (cf. PARTIAL VEIL).

VAM – vesicular arbuscular mycorrhizal (endomycorrhizal) – more correctly AM or arbuscular mycorrhizal, since not all fungi producing this kind of mycorrhiza have vesicles.

VECTOR – an organism which consciously or unconsciously aids in the dispersal of another, e.g., dipteran flies are vectors for stinkhorns.

VEIL – see ANNULUS (partial veil), VOLVA (universal veil).

VESICULAR-ARBUSCULAR MYCORRHIZAS – endomycorrhizas; plant roots colonized by mutualistic fungi of the Glomales (some of which do not produce vesicles, suggesting that these mycorrhizas should simply be described as ARBUSCULAR MYCORRHIZAS).

VIRULENCE – the degree or measure of pathogenicity.

VOLVA – a sheath around the base of the stipe in some agarics, esp. the poisonous Amanita; remains of the universal veil.

WHITE ROT – a wood rot produced by basidiomycetes that can degrade both cellulose and lignin.

WILT – a plant disease, caused by species of Verticillium and Fusarium (Hyphomycetes), characterized by loss of turgidity and collapse of leaves.

XEROTOLERANT – able to grow under dry conditions.

XYLEM – lignified water-conducting tissue in vascular plants.

YEASTS – fungi which in many cases are unicellular, though some produce hyphae; most yeasts are anamorphs; their cells are conidia, and they multiply by various kinds of conidiogenesis. Some can produce asci, some can form basidia, and some appear to be anamorphic holomorphs — entirely asexual.

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Great class! I did Ja's cultivation class at the end of march and my mycelium is growing as we speak! Great class Ja and Maria, the location was amazing the food fantastic and the people so friendly. Have a great tour and keep spreading the Fungi!
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Highly recommended! I did a work trade for Ja for one of the cultivation workshops in Eugene and learned more by helping out than I would have by just being in the workshop!!
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